Grinding method and means



Jan. 10, 1933. T. B. SMITH GRINDING METHOD AND MEANS Filed June 15, 1929 2 Sheets-Sheet l INVENTOR Theodom B. Smith ATTOR N EY Jan. 10, 1933. SMITH 1,894,067

GRINDING METHOD AND MEANS Filed June 13, 1929 2 Sheets-Sheet 2 INVENTOR T h godore B. Smith ATTORN EY Patented Jan. 10, 1933 UNITED STATES PATENT THEODORE B. SMITH, OF GREAT NECK, NEW YORK, ASSIGNOR TO JOHN HASSALL, INC., OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK GRINDING METHOD AND MEANS Application filed June 13, 1929. Serial No. 370,532.

This invention relates to grinding methods and means, and more especially to an operative method and device for grinding a conical-shaped notch in a die adapted to form the point of a nail by pressure.

An object of the invention is to provide a means for directing a suitable grinding edge in such manner that it will grind successively each of the two halves of a completed die in which a piece of wire may be pointed at one end during its manufacture into a nail.

Another object is to provide a method of forming such a concavity in a die that will be absolutely symmetrical and of proper tapered-shape and adapted for adjustment to any length, width and taper of hole in such die.

All these and other objects as suggested herebelow, areattained by the methods and means now to be described and illustrated in the accompanying drawings, in which Figure 1 is atop plan view of the essential operating features of the complete adj ust able grinder, adapted for the specific use suggested above.

Fig. 2 is a side elevational view of the embodiment shown in Fig. 1.

Fig. 3 is a fragmentary detailed view taken through the line 33 of Fig. 4, and showing the work-holding member in one of its eX- treme positions.

Fig. 4 is a fragmentary sectional View through the line 4- -4 of Fig. 3, showing the constructional features of the adjusting device for altering the slope or taper of the notch to be ground.

Fig. 5 is a sectional view through the line 55 of Fig. 6, and showing the work-holding member in the other extreme position to that of Fig. 3.

Fig. 6 is a fragmentary side-elevational view of the worlnholding member positioned as in Fig. 5.

Fig. 7 is a detail view showing, in enlarged scale, the cross-sectional shape of cut and the cutting edge which produces it.

And Fig. 8 is a view similar to Fig. 7, but showing the longitudinal shape of the cut, and a portion of the periphery of the grinding wheel which produces it.

Like numerals refer to like parts through out the several views.

In the manufacture of nails it has heretofore been the practice to employ highly skilled help to grind the dies for forming the conical points of the nail, these dies being used on the wire from which the nails are made to press the points therefrom. Such dies are made in two half-sections meeting along av longitudinal plane through the aizis of the tapered notch. Absolute accuracy is essential, and it therefore takes considerable experience for a highly skilled mechanic to be able to cut the dies by hand.

The present invention comprises a novel and exceedingly practical device for accomplishing this work largely automatically and with utmost accuracy and precision. It employs a new and novel method of abrasion whereby the cutting tool or abrading surfacesuch as the grinding wheel-is caused to move through an angle of exactly 90 during the other part of said operation, and through an adjacent 90 during the other part of said operation. By this means a complete semi-circular notch, adjusted to cut any taper desired, is obtained in the face of thedie.

The device consists essentially of a grind ing wheel 10 mounted upon its bearing or shaft 11, and caused to rotate by a belt, for

instance, over its pulley 12; also a companion grinding wheel 13, with its revolvable shaft 14, by means of its pulley 15. The cutting surface or periphery of the grinding wheels 10 and 13, are beveled substantially at an angle of as shown; or it may be beveled at any other smaller angle.

The work-holding mechanism comprises a vertical bearing 16 rotatably carrying a vertical pin or shaft within collar-like fillers 17, having attached to the upper end of the shaft at right angles thereto work-holding member 18 having a flat upper surface, and a pair of spaced upwardly-extending sliding surfaces 19, between which the die 20, Fig. 4,

is adapted to be firmly held in sliding engagement. The central vertical plane of slide member 19 is positioned in the plane of the larger diameter surface of grindmg wheel 10, so that the extreme edge of the wheel comes midway between the slide surfaces of member 19.

Attached near the outer end of member 5 18 is a handle 21 by means of which member 18 is swung about its pivot during the operation of grinding the one half part of the half tapered hole in the half die 20.

Associated with the grinding wheel 10 are 10 die holding members similar to those just described, for grinding wheel 13, these being the vertical pivot or shaft 22 the right-angularly extending member 23 corresponding to member 18, and the slide member 24 corresponding to slide 19.

In the disclosure of Fig. 1, member 18 is shown as mounting a grinding wheel dressing tool 25, having one or more cutting points 2626, made of diamond or other abrading material, adapted to face off with precision, the grinding surface 10 when same has worn sufliciently to need such dressing; this dressing tool may of course be applied similarly to the surface of wheel 13.

Member 18 is pivoted to move through exactly one quarter of complete circle, by carrying a downwardly-extending pin 27, Fig. 2, which engages in its outward extreme position a stop member 28, and in its inward extended position the side of shaft 29.

The extent of taper of the hole cut into the die 20 by the grinding wheel is determined by an adiustment comprising an adjusting screw 30, Fig. 4, arranged as shown, and a spiral spring 31 adapted to swing the pivoting shaft of member 18 in a vertical plane about shaft 29. This tilts the face of die 20 which comes in contact with grinding wheel 10 at any angle desired and so alters the taper of the notch cut therefrom. This adjustable tapering movement is accomplished in conjunction with a vertical movement of die holder 19 and its attendant parts, which in turn is accomplished by means of putting in or taking out filler collars 17 to raise or lower member 18 in relation to shaft 29. It is to be noted that the vertical adjustment by means of the filler collars 17 when used alone will fix a certain depth of cut in proportion to a length of out, which may or may not be the desired proportion. However, in conjunction with the pivoting adjustment about shaft 29, any combination of depth of cut, length of cut, and taper, may be readily obtained.

. The method of operation is simplicity itself.

The die member 20 is positioned in the slide holding members 19, the adjustment made as to taper and depth and length of cut, the power turned on to revolve the grinding wheel and the tool 20 then fed slowly by hand into the surface of the revolving wheel and at the same time die holding member 18 is swung about a 90 arc by means of handle 21.

Successive operations of this kind soon grinds one half of the half die tapered notch necessary for this half of the die. Tool 20 is then transferred to the tool-holding member of the adjacent oppositely-facing grinding wheel 13 and these operations repeated to grind the other half of the half tapered hole of this die member. Two such die members 'of course make up the complete die for use in pointing the nail.

it is to be understood that the present disclosure is for purpose of illustration only, and that the invention is not limited thereto. To those skilled in the art, many modifications of the invent-ion will be readil apparent, and it will also be obvious to suc skilled persons that parts of the device and method may be used without other arts thereof, many such combinations readily suggesting themselves. Therefore, it should be, and is to be distinctly understood that for a definition of the limitations of the invention, reference must be had to the appended claims.

Having now described the invention, what is claimed as new, and for which Letters Patent of the United States is desired, is:

1. The method of grinding a tapered notch in a right angular surface, including moving the surface through 90 in a plane at right angles. to that of a revoluble grinding tool having a frusto-conicai peri heral face to cut one half of the tapered notch, and then moving it through the adjacent 90 against a second similar grinding tool in reverse position to out the other half of the tapered notch.

2. A grinding machine, comprising two parallel rotatable grinding wheels, the cutting edge of each of which is tapered at an angle of 45 in opposite directions, and means for rotating the surface to be ground about a plane at right angles to the plane of rotation of the grinding wheel on a pivot in the plane of the extreme outer peripheral edge of said wheel.

3. The method of cutting a tapered notch, including moving the material to be cut into contact with the cutting surface of a revoluble grinding wheel having a diameter sufficiently large so that the length of cut is but a small part of the total circumference of the wheel, and pivoting the material to be cut at right angles to the plane of rotation of the grinding wheel against a second similar grinding wheel in reverse position to form a hole tapered longitudinally and arc-shaped in cross-section.

4. In combination, a grinding wheel, means for moving an article to be ground against the surface of the wheel along a chord thereof, means for raising and lowering the position of the article to alter its chord-like path with relation to the center of the wheel, and means for tilting the article into a chord-like path at an angle to the first-mentioned path.

5. The combination in a die grinding machine of a pair of grinding wheels beveled substantially at an angle of 45 and adapted to be rotated in proximity to each other by independent drive means, a work holding mechanism comprising a Vertical pin within collar-like fillers, a work-holding member attached to the pin, together with a pair of sliding surfaces between which the die is adapted to be firmly held in sliding engagement.

Signed at New York in the county of New York and State of New York, this 10th day of J une, 1929.

THEODORE B. SMITH. 

